Wave energy conversion system

ABSTRACT

A wave energy conversion system converts wave energy within a wave medium into electrical energy. The wave energy conversion system includes a base substantially connected to a wave-medium floor, a tidal platform connected to said base and a tidal float connected to said tidal platform. An axle is connected to said tidal platform with an inductive coil positioned within the axle, such that an axis of the inductive coil is parallel to the axle. A magnetic sleeve includes a magnetic sleeve opening, such that the axle passes through the magnetic sleeve opening. A float member is connected to said magnetic sleeve. A wave moving through the wave causes displacement of the float member, causing the magnetic sleeve to move relative to the inductive coil and generate electrical energy within the inductive coil.

TECHNICAL FIELD OF THE INVENTION

The invention relates to wave-energy conversion devices, particularly topoint absorber wave-energy conversion systems, comprising in part anunderwater device which derives power from buoyancy variations arisingfrom changes in pressure caused by waves and/or changes in the level onthe surface above and which reacts against a platform that changes levelin accordance with tidal level changes.

BACKGROUND OF THE INVENTION

The petroleum crisis in the early 1970's was the impetus for significantinnovation in wave energy conversion systems. A lack of practicalsolutions or reasonable prospects of efficient and robust technologies,plus declining oil prices, eventually led to a general disenchantment inthe viability of wave-energy conversion.

Research continued at a few largely academic centers and over the pasttwenty-five years a great deal has been learned. Both theoreticalunderstanding of sea waves and technical expertise in related marineengineering has gained immeasurably from the offshore oil and gasindustries during the same period. Growing concern with global climatechange has led to an increased sense of urgency in the quest forcommercially viable renewable energy sources.

The theoretical potential of wave energy has been recognized for manyyears. The size of this resource has been estimated to be 219 gigawattsalong the coats of the European Union, or more than 180 terawatt hourseach year. The wave power off the west coasts of Ireland and Scotland,where the winter resource is approximately twice that available duringsummer months, ranks with the highest levels per kilometer in the World.

Wave energy is lost by friction with the sea bottom as the sea becomesshallow, with water depths of half a wavelength or less. This is mostpronounced where wavelengths tend to be long, as off the NW coast ofEurope.

Research and development into wave energy converters (WECs) over thepast twenty-five years, plus the knowledge and practical experiencegained from the off-shore oil and gas industries, has now reached astage where robust and effective wave energy converters with installedcapacities of one megawatt and greater are being developed.

The wave energy resource may be split into three broad categories, basedon where the energy from waves may be recovered: 1. in the open sea,i.e. offshore; 2. on or close to the shore line, i.e. on-shore orinshore; 3. outside the normal area of breaking waves but not in thedeep ocean, i.e. near shore.

A fourth category, not generally considered in the context of waveenergy converters, but which may be of relevance to this presentinvention, is waves or surges in a liquid contained in vessels andtanks.

The very large number of devices and concepts proposed to date has beenclassified and described in summary form for the Engineering Committeeon Oceanic Resources by the Working Group on Wave Energy Conversion(ECOR draft report, April 1998). This follows a similar classificationbased on the intended location, i.e. off-shore, near shore to off-shore,and on-shore.

Wave Energy Converters (WECs) may also be classified in different waysaccording to their operating principle and the ways in which they reactwith waves. In terms of practical application, only a very few types ofdevice are presently, or in the recent past have been, in use or undertest in European waters.

By way of illustration, two different but overlapping classes will bebriefly commented on: the Oscillating Water Column (OWC) devices andPoint Absorbers, the latter being the relevant class in the presentcontext.

OWC devices are typically those where the wave is confined in a verticaltube or a larger chamber and, as it surges back and forth, drives airthrough a power conversion device. Megawatt-scale OWC devices are now atan advanced stage of development.

One such device, being built in a rocky gully on the western shore ofPico in the Azores, is a reinforced concrete chamber partly open at oneside to the waves, and with two turbines above and behind through whichthe confined air is forced. These are specially developed Wells turbines(one with variable blade pitch) and on the whole would seem to be thebest-developed and perfected conversion system available today. It is,however, unlikely that any one such installation will have an installedcapacity greater than two megawatts and the number of suitable sites hasto be extremely limited.

Point absorbers may react against the sealed (therefore necessarilysited near-shore), or be floating and self-reacting. Theoreticalanalysis has greatly increased our understanding of point absorbers.

Point absorbers are usually axi-symmetric about a vertical axis, and bydefinition their dimensions are small with respect to the wavelength ofthe predominant wave. The devices usually operate in a vertical mode,often referred to as ‘heave’. As such they are capable of absorbingenergy arising from changes in the surface level rather than fromforward motion of breaking seas.

The theoretical limit for the energy that can be absorbed by anisolated, heaving, axi-symmetrical device has been shown to depend onthe wavelength of the incident waves rather than the cross section ofthe device, i.e. from the wavelength divided by 2. pi. Thus thewavelength is a critically important criterion, resulting in theattraction of locating the point absorber devices well outside theregion of breaking waves, and where they will be open to long wavelengthocean swell or ‘heave’.

A point absorber device may react against the inherent inertia of one ofits components, or against the bottom of the sea. Thus, point absorbersmay be deployed near-shore in contact with the sea-bed or, in the caseof self-reacting devices, near-shore or off-shore.

Small-scale practical point absorbers such as fog horns and navigationbuoys, both of which may incorporate OWCs, have been in use for decades.Typically these have a power of a few hundred watts.

One new point absorber device, now claimed to be capable of generatingof the order of a megawatt, has been described. This is based on thebuoyancy variations of a submerged, partly air filled, rigid vessel openat the bottom. Initially the device is floating with neutral buoyancy ata certain depth.

If a wave passes above it the pressure around this vessel increases andwater will flow into the vessel, displacing the air or gas inside (whichis free to flow to a large reservoir or to similar devices linked bypipelines), decreasing the air volume in it and hence its buoyancy. Theupthrust experienced has decreased in proportion to the volume of waterdisplaced, i.e. Archimedes' principle. The partially filled vessel willstart to sink. When a trough passes above it the reverse process occurs,and the vessel tends to rise to recover its rest position.

The size of the forces exerted will depend on the extent of the watersurface within the vessel, the amplitude of the wave and the frequencyof waves. The wave energy transformer is described in terms of twosimilar containers, horizontally displaced, such that the gas displacedfrom one container passes to the second. Essentially the gas, being freeto move between two or more similar devices remains under constantpressure, as required by the depth below the surface.

This is a heavily engineered device, one that will not readily flex withthe lateral movements of water as found below waves, it is notindependent of the seabed and is not independent of tidal changes inmean sea level. The base or center of the device is fixed in itsposition with respect to the seabed.

A common problem with existing devices designed to harvest significantamounts of energy from the sea is their complexity and cost. They arepredominantly large structures, with rigid components, placed in a harshenvironment. There is little use of well-proven components. Most devicesproposed are very demanding in terms of engineering design, deploymentand maintenance.

Other known devices which are used in the marine environment, althoughnot designed for the conversion of wave energy to usable power includedevices designed to pump fluids from the sea-bed.

The term “wave motion” as used herein refers to both waves on a surfaceof a liquid and swell in a body of a liquid.

Ocean waves represent a significant energy resource. It is known to usea Wave Energy Converter to extract power from such waves. Known WaveEnergy Converters tend to be expensive, and have limited prospects forsurvival in extreme conditions.

A variety of devices may be used to provide relatively small amounts ofpower for use in small devices intended for long life in inaccessiblelocations. For example, to perform long endurance military missions,small unattended sensors or robots need more electrical power to sense,communicate, or move than they can practically carry in a pre-chargedpower storage device. This means that they must be able to harvestenergy from their environment during the mission to periodicallyre-charge their power sources.

The small size of the devices typically used in military systems makesit difficult to collect a useful amount of power since natural energyusually occurs as a “flux”, and the amount available for collectiondepends on the physical capture area.

The amount of energy or power available in waves is enormous and thispower is generally recognized by the damage caused. Thus, waves areusually regarded as a hindrance rather than an asset. For example, atWick Breakwater in Scotland a block of cemented stones weighing 1,350tons was broken loose and moved bodily by waves. Several years later, areplacement pier weighing 2,600 tons was carried away.

In other instances, a concrete block weighing 20 tons was liftedvertically to a height of 12 feet and deposited on top of a pier 5 feetabove the highwater mark; stones weighing up to 7,000 pounds have beenthrown over a wall 20 feet high on the southern shore of the EnglishChannel; and on the coast of Oregon, the roof of a lighthouse 91 feetabove the water was damaged by a rock weighing 135 pounds.

Heretofore this enormous amount of power available in the world's oceanshas been largely ignored. One reason for this lack of utilization of theavailable energy in the world's oceans is their very power. In otherwords, most devices which have been designed for capturing or convertingthe energy of waves to useful work have been destroyed or damaged bythat very energy.

This is at least partly due to the irregularity of waves which can causejerky or irregular motion of wave energy devices. Moreover, stormsfrequently occur during which time wave action can become violent, thusdestroying installations erected for converting the energy of the wavesto useful work.

Other prior art devices are not efficient in operation and convert onlya very small portion of the available wave energy. For example, theactual propagation or movement of water particles in a lateral directionis only about one percent of the velocity of travel of waves. Thus,while devices floating on the surface of a body of water may be utilizedto extract some of the energy of the waves themselves, these devices arenot able to extract energy from the moving water itself.

Prior art devices range from elongate cylinders or like structuresbobbing at the surface of the body of water for driving a propellercarried thereby, through so-called air turbines which comprise floatingbodies at the surface with open bottom chambers into which waves arepermitted to rise and fall for alternately compressing air in chambersto drive a turbine, up to complex bodies specifically configured toobtain rotational movement from the action of waves and moving waterparticles thereon to drive turbines. These last devices are commonlyreferred to as Salter's Duck.

All such prior art devices capture or convert only a small portion ofthe available power in waves and in many cases are not durable enough towithstand the forces encountered in the ocean's waters or are not costefficient.

Another device provides a structure which floats at the surface of abody of water and is constructed to convert the rolling or orbitalmotion of water particles in the waves into a linear flow of water andto then accelerate the linear flow without using any mechanical means orprocess. The accelerated flow is then utilized, inter alia, to drive awater wheel, turbine or the like for extracting power from the movingbody of water.

Another known a device for the conversion of the energy of thegravitational waves, i.e. sea and ocean wind-formed waves, or dead orground sea swell in which a series of input parallel converters areconnected by means of an input collector manifold with a turbogeneratorwhich on its turn is connected by means of an output collector-manifoldto a series of parallel output converters which let out the water in thelow part of the wave. In such devices, the input and output convertershave independent sources of gas under pressure. The device is maintainedat a given level by means of a ballast system fitted to the convertersand stabilizers.

The disadvantage of this device is the large number of input and outputelements which makes this device very complicated. Furthermore, the flowshould surmount the local resistances in its inflow in the input andoutflow from the output collector or manifold as a result of which thereoccurs a decrease in the harnessed energy.

Another shortcoming of such a known device is that the independentsources of gas under pressure maintain the water in the input and outputconverters and this can vary over a wide range. When the level is verylow, part of the gas can flow out of the converters and this results ina loss of part of the compressed air. Conversely, when we have a highlevel and a little volume of the gas cushion, the latter is inferior inits role as buffer and energy accumulator.

Furthermore, this device cannot be directed at a specified angle towardsthe wave front, and in this way an important reserve for increasing itssmoothness of operation and improving its efficiency cannot be utilized.

In the past, research performed on ocean thermodynamics revealed thatenergy costs would surpass energy production for the then known oceanwave producing energy systems. In one known system, a floating tank isprovided with an opening at the top of the tank which leads into apassage extending through the center of the tank where a propeller-likeblade is mounted.

The action of the ocean waves causes water to flow into the opening atthe top of the tank where such water falls onto the blade to rotate itand consequently produce electrical energy. One limitation of thissystem is that it can utilize only the amount of ocean water that flowsinto the tank opening to provide the dynamic force on the propellerblade, rather than being able to use the full force of the ocean wave.

Generating technologies for deriving electrical power from the oceaninclude tidal power, wave power, ocean thermal energy conversion, oceancurrents, ocean winds and salinity gradients. Of these, the three mostwell-developed technologies are tidal power, wave power and oceanthermal energy conversion.

Tidal power requires large tidal differences which, in the U.S., occuronly in Maine and Alaska. Ocean thermal energy conversion is limited totropical regions, such as Hawaii, and to a portion of the Atlanticcoast. Wave energy has a more general application, with potential alongthe California coast. The western coastline has the highest wavepotential in the U.S.; in California, the greatest potential is alongthe northern coast.

Wave energy conversion takes advantage of the ocean waves causedprimarily by interaction of winds with the ocean surface. Wave energy isan irregular and oscillating low-frequency energy source that must beconverted to a 60-Hertz frequency before it can be added to the electricutility grid.

Although many wave energy devices have been invented, only a smallproportion have been tested and evaluated. Furthermore, only a few havebeen tested at sea, in ocean waves, rather than in artificial wavetanks.

As of the mid-1990s, there were more than 12 generic types of waveenergy systems. Some systems extract energy from surface waves. Othersextract energy from pressure fluctuations below the water surface orfrom the full wave. Some systems are fixed in position and let wavespass by them, while others follow the waves and move with them. Somesystems concentrate and focus waves, which increases their height andtheir potential for conversion to electrical energy.

A wave energy converter may be placed in the ocean in various possiblesituations and locations. It may be floating or submerged completely inthe sea offshore or it may be located on the shore or on the sea bed inrelatively shallow water. A converter on the sea bed may be completelysubmerged, it may extend above the sea surface, or it may be a convertersystem placed on an offshore platform. Apart from wave-powerednavigation buoys, however, most of the prototypes have been placed at ornear the shore.

The visual impact of a wave energy conversion facility depends on thetype of device as well as its distance from shore. In general, afloating buoy system or an offshore platform placed many kilometers fromland is not likely to have much visual impact (nor will a submergedsystem). Onshore facilities and offshore platforms in shallow watercould, however, change the visual landscape from one of natural sceneryto industrial.

The incidence of wave power at deep ocean sites is three to eight timesthe wave power at adjacent coastal sites. The cost, however, ofelectricity transmission from deep ocean sites is prohibitively high.Wave power densities in California's coastal waters are sufficient toproduce between seven and 17 megawatts (MW) per mile of coastline.

As of 1995, 685 kilowatts (kW) of grid-connected wave generatingcapacity is operating worldwide. This capacity comes from eightdemonstration plants ranging in size from 350 kW to 20 kW. None of theseplants are located in California, although economic feasibility studieshave been performed for a 30 MW wave converter to be located at HalfMoon Bay. Additional smaller projects have been discussed at Fort Bragg,San Francisco and Avila Beach. There are currently no firm plans todeploy any of these projects.

As of the mid-1990s, wave energy conversion was not commerciallyavailable in the United States. The technology was in the early stagesof development and was not expected to be available within the nearfuture due to limited research and lack of federal funding. Research anddevelopment efforts are being sponsored by government agencies in Europeand Scandinavia.

Many research and development goals remain to be accomplished, includingcost reduction, efficiency and reliability improvements, identificationof suitable sites in California, interconnection with the utility grid,better understanding of the impacts of the technology on marine life andthe shoreline. Also essential is a demonstration of the ability of theequipment to survive the salinity and pressure environments of the oceanas well as weather effects over the life of the facility.

Wave energy could easily replace fossil fuel energy in some areas alongcoasts, cutting down on greenhouse gas emissions and the atmosphericpollution caused by burning fossil fuels. The effects on the environmentare generally minor, as the construction of a wave energy plant requiresabout the same area as a small harbor.

Ocean waves are created by the interaction of winds with the surface ofthe sea. They contain large amounts of energy stored in the velocity ofthe water particles and in the height of the mass of seawater in a wavefront above the mean level of the sea (E.S.B.I. and E.T.S.U., 1997).

The amount of wind energy that can be transferred to the surface of theocean to create the waves depends upon the wind speed, the distance overwhich it interacts-known as the fetch—and the duration for which itblows over the water. Due to the direction of the prevailing winds andthe size of the Atlantic Ocean, North Western Europe including Britainand Ireland have one of the largest wave energy resources in the world(E.S.B.I. and E.T.S.U., 1997).

There are significant differences in seasonal levels of wave energy, butthe long term output should be somewhat more predictable than with someother renewable resources (E.S.B.I. and E.T.S.U., 1997).

The principal ways of extracting energy from waves rely eitherseparately or jointly on the surge, heave and pitch of the waves. Thefrequency of arrival of ocean waves is low (a few per minute). Aselectrical generators rotate at hundreds of revolutions per minute theconversion mechanism must produce a higher frequency rotation togenerate electricity-which is a convenient energy transfer medium. Thiscan be done by hydraulic pumps or pneumatic bags/chambers driving higherspeed turbines and generators.

Such conversion mechanisms have been tested by the construction of manyvarieties of experimental laboratory models and by some small-scaledevices in the open sea or large lochs.

Currently there are two types of shoreline device in operation. One is ashoreline or caisson breakwater oscillating water column driving apneumatic Wells turbine in 10 to 25 metres of water. The second type isa tapered channel device that was developed in Norway. In this type,incoming waves travel up a tapering channel, overflow and fill a higherlevel reservoir. The enclosed water then drives a Kaplan hydroelectricturbine as it returns to the sea.

A floating offshore device known as the circular clam has been developedby Sea Energy Associates and Coventry University, Britain. The designcomprises a floating twelve-sided hollow ring. Each of the twelve sideshas a flexible membrane that inflates and deflates with the incomingwave action. The air passes via a central circular manifold throughWells turbines, which drive electrical generators.

In the long term, wave conversion devices positioned in deep wateroffshore may provide the most likely method of large scale energyrecovery. Development of shoreline and near shore systems is, however,relatively further advanced although considerable proving work remainsto be done if these are to be considered as reliable sources ofelectricity (E.S.B.I. and E.T.S.U., 1997).

SUMMARY OF THE INVENTION

A wave energy conversion system converts wave energy within a wavemedium into electrical energy. The wave energy conversion systemincludes a base substantially connected to a wave-medium floor, a tidalplatform connected to said base and a tidal float connected to saidtidal platform. An axle is connected to said tidal platform with aninductive coil positioned within the axle, such that an axis of theinductive coil is parallel to the axle. A magnetic sleeve includes amagnetic sleeve opening, such that the axle passes through the magneticsleeve opening. A float member is connected to said magnetic sleeve. Awave moving through the wave causes displacement of the float member,causing the magnetic sleeve to move relative to the inductive coil andgenerate electrical energy within the inductive coil.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and theadvantages thereof, reference is now made to the following descriptiontaken in conjunction with the accompanying Drawings in which:

FIG. 1 illustrates a wave energy conversion device;

FIG. 2 illustrates a wave energy conversion system;

FIG. 3 illustrates an overhead view of a wave energy conversion system;

FIG. 4 illustrates a wave energy conversion system;

FIG. 5 illustrates a functional block diagram of a wave energyconversion system;

FIG. 6 illustrates a head element of a wave energy conversion device;

FIG. 7 illustrates a head element of a wave energy conversion device;

FIG. 8 illustrates a functional block diagram of an output system;

FIG. 9 illustrates a circuit diagram of an output system;

FIG. 10 illustrates a voltage output of a wave energy conversion device;

FIG. 11 illustrates a rectified voltage output of a wave-energyconversion device;

FIG. 12 illustrates a wave-energy conversion device use;

FIG. 13 illustrates a wave-energy conversion system use;

FIG. 14 illustrates a wave-energy conversion system use;

FIG. 15 illustrates a side cutaway view of a magnetic sleeve;

FIG. 16 illustrates a top cutaway view of a magnetic sleeve;

FIG. 17 illustrates a top cutaway view of a magnetic sleeve with abearing device;

FIG. 18 illustrates a wave energy conversion device;

FIG. 19 illustrates a cutaway view of a wave energy conversion device;and

FIG. 20 illustrates a wave-energy conversion system.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, wherein like reference numbers are usedto designate like elements throughout the various views, severalembodiments of the present invention are further described. The figuresare not necessarily drawn to scale, and in some instances the drawingshave been exaggerated or simplified for illustrative purposes only. Oneof ordinary skill in the art will appreciate the many possibleapplications and variations of the present invention based on thefollowing examples of possible embodiments of the present invention.

With reference to FIG. 1, a wave energy conversion device 100 inaccordance with the preferred embodiment is shown. The wave energyconversion device 100 includes a generally vertically positioned centralwave displacement axle 102.

The central wave displacement axle 102, in accordance with the preferredembodiment, is a hollow rigid pole. The diameter of the central wavedisplacement axle will typically be about one inch, although thedimensions of the wave energy conversion device 100 and the central wavedisplacement axle will depend primarily on the depth of thewave-producing body of water and the intensity of the waves at the pointof implementation.

The central wave displacement axle 102 may be formed of metal, plastic,composite materials or other substances. Typically, the material used toform the central wave displacement axle 102 should be sufficiently rigidto maintain its shape under the kinds of forces that may be present insubsurface wave action. Because the environment of a wave-producing bodyof water, particularly in the ocean with salt-rich sea-water, isparticularly harsh, the choice of material will require consideration ofseveral factors, including strength, weight and durability in themedium.

A buoyant collar float 106 is attached to an upper end portion of thecentral wave displacement axle 102. In accordance with the preferredembodiment, the buoyant collar is a cylindrical float with a hollowinterior, such that the buoyant collar 106 may move along the centralwave displacement axle 102 inserted through the hollow interior of thebuoyant collar float 106.

The buoyant collar 106 may be designed to have a specific gravity lessthan the wave medium 104, such that the buoyant collar tends to risewhen submerged in the wave medium 104 and float on the wave medium whennot subjected to other pressures. Typically, the buoyant collar 106 ismade from a substance that contains significant gas content, such asStyrofoam, or an elastic material like a balloon containing gas. Thebuoyant collar 106 may be configured as an inverted milk bucket withholes.

As the wave medium 104 moves, the buoyant collar 106 moves vertically onthe central wave displacement axle 102 as the buoyant collar 106 issubjected to pressures from the moving wave medium 104.

The buoyant collar 106 may typically fashioned in a foam-filledcontainer or a gas-filled container. A person having skill in the artwill appreciate that the buoyant collar 106 may be fashioned in avariety of shapes and designs, as well as lending itself to being madefrom a variety of materials. Choice of the materials will depend onimplementation details of the particular embodiment.

The buoyant collar 106 is attached by attachment lines 110 to a magneticsleeve 112. In accordance with the preferred embodiment, the buoyantcollar 106 is attached to the magnetic sleeve 112 by four attachmentlines 110, each connected at the end points of perpendicular diametersof the magnetic sleeve 112.

The particular arrangement of the attachment lines 110 for a givenembodiment will depend on the details of the implementation. Theattachment lines 110 may be wires, rods, cords, string, line or anyother medium capable of attaching the buoyant collar 106 to the magneticsleeve 112.

In accordance with one embodiment, the attachment lines 110 are madefrom a stiff material, such as aluminum or steel, such that when thebuoyant collar 106 descends along the central wave displacement axle102, the magnetic sleeve 112 is pushed down by the attachment lines 110.

Flexible materials such as cord or line may be used for the attachmentlines 110, as the weight of the magnetic collar tends to cause themagnetic collar 112 to descend along the central wave displacement axle102.

Magnetic sleeve 112, in accordance with the preferred embodiment, is ahollowed cylinder made from a magnetic substance, such as magnetizediron. Typically, the magnetic substance will be a ferromagnetic alloy,although other magnetic materials may be used as appropriate ordesirable.

The magnetic substance may be covered with a plastic or other coveringto protect the magnetic substance from the wave medium 104. The interiordiameter of the magnetic sleeve 112 is typically larger than theexterior diameter of the central wave displacement axle 102, such thatthe magnetic sleeve 112 may move freely over the length of the centralwave displacement axle 102 inserted through the magnetic sleeve 112.Ball bearings or other forms of lubricative mechanism may be implementedbetween the magnetic sleeve 112 and the central wave displacement axle102.

Within a hollow portion of the central wave displacement axle 102 is aninductive coil 114 of electrically conductive wire. The inductive coil114 may extend through the hollow portion of the central wavedisplacement axle 102 from the lower limit of the magnetic sleeve'smotion 116 and the upper limit of the magnetic sleeve's motion 108.

An inductive coil 114, typically less than the length of the full rangeof motion of the magnetic sleeve 112, may be used. An inductive coil 114more than the length of the full range of motion of the magnetic sleeve112 may be used.

The type of electrically conductive wire and dimensions of the inductivecoil 114 are determined by the embodiment. In another embodiment, theinductive coil 114 may be embedded in the material of the central wavedisplacement axle 102.

Where the central wave displacement axle 102 is made of metal,particularly conductive metal, the electrically conductive wire formingthe inductive coil 114 is insulated from conductive contact with thecentral wave displacement axle 102. The inductive coil 114 iselectrically connected to transmission wires 118. The transmission wires118 provide current to a connector 120.

The motion of the magnetic sleeve 112 along the central wavedisplacement axle 102 is limited at one end by an upper axle collar 108and at the other end by a lower axle collar 116. The upper axle collar108 and the lower axle collar 116 are typically formed by an expandedportion of the central wave displacement axle 102. Other forms of motionlimiting may be used, as appropriate to the central wave displacementaxle 102 and the magnetic sleeve 112.

As the magnetic sleeve 112 passes along the surface of the central wavedisplacement axle 102 with the inductive coil 114 positioned within thecentral wave displacement axle 102, electric current is generated in theinductive coil 114 by induction. The magnetic field of the magneticsleeve 112 moves through the inductive coil 114, creating anelectromagnetic field in the inductive coil 114, resulting in a voltagedifferential and an electrical current, through the wire.

The magnitudes of the voltage differential and electrical currentcreated is determined by the magnetic qualities of the magnetic sleeve112, the details of the inductive coil 114 and the length and speed ofthe vertical displacement of the magnetic sleeve 112 along the centralwave displacement axle 102.

As the wave medium 104, typically seawater at or near an ocean shore,undulates in depth, the vertical wave motion 124 creates vertical axlemotion 126 in the buoyant collar 106. The attachment of the buoyantcollar 106 to the magnetic sleeve translates the vertical axle motion126 of the buoyant collar to vertical sleeve motion 128.

The vertical sleeve motion 128 causes the magnetic sleeve 112 to movealong the axis of the inductive coil 114 within the central wavedisplacement axle 102, generating electrical current in the inductivecoil 114. The electrical energy generated passes through thetransmission wire 118 to output circuits. The generated electricalenergy available at the output interface 120 is fed to an electricaloutput circuit that captures, stores or otherwise uses the electricalcurrent.

Buoyant collar float 106 comprises a buoyant member, typically designedto provide variable buoyancy under the surface of the body of liquid104. The buoyant collar float 106 may contain a constant mass of gas,the volume of which is dependent on the pressure exerted by the body ofwave-medium 104. A varying pressure will result in a change in volume ofthe gas, a change in volume of the elastic member and a resultant changein buoyancy of the buoyant collar float 106.

In accordance with one embodiment, buoyant collar float 106 may be aballoon type structure, made of, or partly made of, elastic or otherwiseflexible material that may change in shape and size according to thepressure exerted on the gas contained therein.

In accordance with one embodiment, the balloon-type buoyant collar float106 may be held in a net cage and shaped so as to maximise the pointeffect, i.e. minimise the diameter of the buoyant collar float 106 withrespect to the wavelength of the over-passing wave in the wave-medium104, from the prevailing wave climate.

Central wave displacement axle 102 is connected at the bottom to ahorizontal stabilization platform base 206. The connection of thecentral wave displacement axle 102 and the horizontal stabilizationplatform base 206 may be a solid connection, such as a weld, or apivoted connection, to allow the central wave displacement axle to moverelative to the horizontal stabilization platform base 206.

In the shown embodiment, the horizontal stabilization platform base 206is hollow to allow transmission wires 118 to be placed therein. Thehorizontal stabilization platform base 206 may be a pipe, a solid plate,a hollowed plate, a grid of pipes or any other configuration suitablefor holding one or more wave energy conversion devices 100.

With reference to FIG. 2, a wave energy conversion system 200 is shown.The wave energy conversion system 200 is submerged in wave medium 104,typically the ocean at or near the shore. In accordance with thepreferred embodiment, the wave energy conversion system 200 is anchoredto the ocean floor 201 using anchors 202. Anchors 202 would typically bemade from concrete or similar compounds. It may be advantageous to useother anchoring devices or systems to anchor the wave energy conversionsystem 200 to the ocean floor 201.

In other embodiments, with a floating horizontal stabilization platformbase, the wave energy conversion system 200 may not be anchored to theocean floor 201. In this embodiment, the wave energy conversion system200 would be attached to floats. The floating wave energy conversionsystem embodiment would be necessary where the wave energy conversionsystem 200 is used in a deep sea environment, where anchoring to theocean floor 201 is impractical.

In the preferred embodiment, the anchors 202 are attached to seabedstabilization posts 204. The seabed stabilization posts 204 aretypically embedded in concrete forming the anchors 202, such that theconcrete solidifies on the seabed stabilization posts to form agenerally heavy and un-detachable anchor 202. In accordance with thepreferred embodiment, the seabed stabilization posts 204 are positionedvertically. In other embodiments, the seabed stabilization posts 204 maybe positioned at another angle.

Seabed stabilization posts 204 act as a motion guide for horizontalstabilization platform horizontal stabilization platform base 206.Seabed stabilization posts 204 extend through a hole or indentation inthe horizontal stabilization platform base 206, such that horizontalstabilization platform base 206 may rise or fall vertically along theseabed stabilization posts 204.

The horizontal stabilization platform base 206 is typically a planarsurface. Horizontal stabilization platform base 206 may be formed of asolid plate of a wave-medium-resistant material. A base may typically beformed of steel, aluminum, plastic, or any other appropriate substance.Horizontal stabilization platform base 206 may be formed as a mesh or asa multi-orifice surface.

The vertical motion of the horizontal stabilization platform base 206along the seabed stabilization posts 204 is typically limited by a lowercollar 212 and an upper collar 214. The lower collar 212 and the uppercollar 214 may be integral with the seabed stabilization posts 204, ormay be created by adding a piece to the seabed stabilization post 204,such that the piece limits the motion of the horizontal stabilizationplatform base 206.

As shown, horizontal stabilization platform base 206 is connected at theextremity to tidal displacement corner posts 208. In the preferredembodiment, horizontal stabilization platform base 206 is formed as asquare, with tidal displacement corner posts 208 situated at the cornersof horizontal stabilization platform base 206. It will be apparent tothose having skill in the art that other configurations of tidaldisplacement corner posts 208 could be used, particularly in otherconfigurations for the base shape.

Tidal displacement corner posts 208 are connected to tidal displacementfloats 210. The tidal displacement floats 210 are typically attached tothe tidal displacement corner posts 208 by a connection device such asrope, or may be fastened in any other appropriate manner.

The tidal displacement floats 210 are sufficiently buoyant to respond tochanges in the wave medium depth by raising or lowering the horizontalstabilization platform base 206. The weight of the horizontalstabilization platform base 206, the tidal displacement corner posts 208and the wave energy conversion devices 100 is sufficiently to keep thehorizontal stabilization platform base 206 generally stable, adjustingto the tidal changes in the wave-medium 104 rather than the wave motion.

Wave energy conversion devices 100 are attached vertically to the base204. In accordance with the preferred embodiment, the wave energyconversion devices 100 are positioned in an array over the surface ofthe base 204. The wave energy conversion devices 100 can be arranged asdensely as free motion permits.

With reference to FIG. 3, an overhead view of wave energy conversionsystem 200 in accordance with the preferred embodiment is shown. Thisembodiment uses a rectangular horizontal stabilization platform base 206with an array of wave energy conversion devices 100 attached to theupper surface of the horizontal stabilization platform base 206.

The wave energy conversion devices 100 may be attached to some or all ofthe adjoining wave energy conversion devices 100 in the array usingconnection lines 216. The connection lines 216 may be nylon line or someother form of cord. The interconnection of wave energy conversiondevices 100 using the connection lines 216 restrict the non-verticalmotion of the wave energy conversion devices 100, reducing the tendencyof the wave energy conversion devices 100 to shift from their verticalposition due to the repetitive forces of the waves. In this embodiment,four tidal displacement floats 210 are situated at the corners of thehorizontal stabilization platform base 206. In another embodiment, thewave energy conversion devices 100 are not connected using connectionlines 216.

With reference to FIG. 4, a simplified wave energy conversion system 200is shown. A median wave-medium level is shown by line 402. The firstwave energy conversion device 100 a is shown at a reference position,such that the distance between the buoyant collar float 106 and themedian level 402 is at a determined height h₀. A wave in the wave-mediumis shown at line 404, such that the depth of the water is lower than themedian wave-medium level above a second wave-energy conversion device100 b and the depth of the water is higher above a fourth wave-energyconversion device 100 d.

With reference to the second wave energy conversion device 100 b, thedepth of the water above the buoyant collar float 106 is h₁, where h₁ isless than h₀. Because the water above the buoyant collar float 106 ofthe second wave energy conversion device 100 b weighs less than thewater above the buoyant collar float 106 of the first wave energyconversion device 100 a, the buoyant collar float 106 of the second waveenergy conversion device 100 b rises. The buoyancy of the buoyant collarfloat 106 is greater than the weight of the water at a depth of h₁.

With reference to the fourth wave energy conversion device 100 d, thedepth of the water above the buoyant collar float 106 is h₃, where h₃ isgreater than h₀. Because the water above the buoyant collar float 106 ofthe fourth wave energy conversion device 100 d weighs more than thewater above the buoyant collar float 106 of the first wave energyconversion device 100 d, the buoyant collar float 106 of the fourth waveenergy conversion device 100 d sinks. The buoyancy of the buoyant collarfloat 106 is less than the weight of the water at a depth of h₃.

When the surface of the wave medium 104 is not flat as in 404, it isequivalent to the occurrence of waves on a water surface. The waveenergy conversion device 100 d is under a crest of a wave 404. As aresult, the height of water column h₃ is greater than h₀. The effect ofthis is the exertion of more pressure on the quantity of gas. Accordingto Boyle's Law pressure times volume (PV) is constant for constanttemperature or, under conditions that will most probably favouradiabatic change, PV.sup. . . . gamma. is constant where gamma tendstowards 1.4 for air. Hence, as the pressure has increased, the volume ofgas within the buoyant collar float 106 contracts.

The height h₃ is equivalent to the height of the wave crest plus anydownward movement of the buoyant collar float 106. Both components of h₃act so as to increase the pressure on the elastic member 106 and cause areduction in volume of the elastic member. According to Archimedes'Principle, as the volume of the elastic member 106 decreases and lessliquid is displaced, the upthrust corresponding to the mass of waterdisplaced will be lessened.

Wave energy conversion device 100 b is under a trough of a wave 404. Theheight h₁ is less than h₀, such that less pressure is being exerted onthe gas, with a resultant increase in the volume of the elastic member106. In a similar manner to that described with relation to wave energyconversion device 100 c, h₁ is made up of two components; the depth ofthe trough and the upward movement of the buoyant collar 106.

The movement of the buoyant collar float 106, which results from using aflexible balloon type arrangement, under the crest and trough adds adynamic effect to the static effect caused by the passage of the passingwave 404.

With reference to FIG. 5, a functional block diagram of the wave-energyconversion system 200 is shown. Electrical energy is generated by therelative motion 128 between the magnetic sleeve 112 and the coil 114.The magnetic sleeve 112 is moved in attachment to a combination ofbuoyant material 106 and weight 130.

The buoyant material 106 tends to cause the magnetic sleeve 112 to rise,while the weight 130 (including the weight of the magnetic sleeve 112)causes the magnetic sleeve 112 to sink. Changes in depth of thewave-medium causes the magnetic sleeve 112 to rise and fall relative tothe coil 114 as the forces on the buoyant material 106 and the weight130 are unbalanced.

The coil 114 is electrically connected to at least an output 250. Thecircuitry and other devices positioned electrically between the coil 114and the output 250 may vary. Typically, the output of the coil will goto a rectifier 218, which creates a positive flow of electricity fromthe random positive and negative flow generated by the random movementsof the magnetic sleeve 112 relative to the coil 114.

Similarly, a regulator 220 may be connected to the output of therectifier 218, to regulate the fluctuations in current output. For mostuses, the output of the regulator 220 will be connected to a storagedevice 224, such as a battery. Stored in a storage device 224, theelectrical energy may be used by any type of electrical device 250.

With reference to FIG. 6, a head assembly of the wave energy conversiondevice 100 is shown. In accordance with the preferred embodiment, themagnetic sleeve 112 has a diameter sufficient to generate electricalcurrent in the coil 114. Relative to the buoyant forces applied bybuoyant collar float 106, the magnetic sleeve 112 has little weight.

With reference to FIG. 7, a head assembly of the wave energy conversiondevice 100 in accordance with another embodiment is shown. In thisembodiment, the magnetic sleeve 112 has a substantially large diameterthan in the embodiment shown in FIG. 6. Relative to the buoyant forcesapplied by buoyant collar float 106, the magnetic sleeve 112 of thisembodiment has a weigh approximately equal to the buoyant forces of thebuoyant collar float 106. This embodiment may be useful in situationswhere the wave energy has a longer frequency.

With reference to FIG. 8, a function block diagram of the output portionof a wave energy conversion system 200 is shown. The circuitrepresentation of the wave-energy conversion device 100 consists of amagnetic sleeve 112 and inductive sleeve 114 represented as a groundedinductor. Resistance in the coil is represented by resistor 226. Eachwave-energy conversion device 100 in a wave-energy conversion system 200may be represented by an equivalent circuit.

Motion of the magnetic sleeve 112 relative to the coil 114 generates avoltage across inductor 114. The voltages generated by each of theinductive coils 114 in a plurality of wave energy conversion devices 100are each fed to a rectifier 218. In one embodiment, the rectifier may bea diode, passing only the positive voltages generated by the wave-energyconversion device 100.

Each of the plurality of rectifiers 218 outputs to a voltage regulator220. The output voltage of the voltage regulator 220 may be fed intoelectrical storage 222, such as a battery or any other energy storagemechanism. In some embodiments, the output voltage of the voltageregulator 220 may be provided directly to an output control 224 or to anoutput device 225.

The electrical storage 222 may be connected to an output control 224,for controlling the use of the output energy. The output of theelectrical storage 222 may be connected directly to an output device225. The output control 224 may be connected to an output device 225.

With reference to FIG. 9, a circuit for the output portion of a waveenergy conversion system 200 in accordance with one embodiment is shown.The wave energy conversion device 100 outputs a voltage with bothpositive and negative voltage components, as shown in the graph of FIG.10. The output voltage of the wave-energy conversion device 100 isconnected across a resistance 226 and the inputs of a rectifier 228.

The arrangement of diodes in the rectifier 228 provides alternatingpaths for positive and negative voltages, such that the output of therectifier 228 is only positive voltages. The output of the rectifier 228is shunted by a capacitor 230 and across the terminals of a storagebattery 232. The electrical energy produced by the wave energyconversion device 100 is thereby stored in the storage battery 232.

With reference to FIG. 10, a graph of a possible voltage output by awave energy conversion device 100 is shown. The vertical axis of thegraph represents the voltage differential between the outputs of theinductance coil 114. A reference line represents a zero voltage, withpositive voltages represented above the reference line and negativevoltages below the reference line. The horizontal axis represents time.

Movement of the magnetic sleeve 112 relative to the inductance coil 114creates voltage at the output of the inductance coil 114, such thatmovement in one direction generates a positive voltage and movement inthe opposite direction generates a negative voltage. The polarity of theinductance coil 114 will determine which direction of movement generatesa positive voltage and which direction of movement generates a negativevoltage.

Because the forces generated by wave motion, particularly in coastalregions where the average wavelength of the waves in the ocean are veryshort, are highly chaotic and random, the voltage changes betweenpositive and negative in rapid and relatively unpredictable fashion. Thespeed of the magnetic sleeve 112 as it moves past the inductance coil112 determines the value of the voltage, such that a magnetic sleeve 112moving at a rapid speed past the inductance coil 112 generates a largervoltage than the same magnetic sleeve 112 moving at a slower speed pastthe inductance coil 112.

The depicted graph represents one possible voltage output, but it shouldbe understood that the voltage output graphs may vary greatly, dependingon the embodiment and the nature of the waves provided.

With reference to FIG. 11, a graph of the same voltage output by a waveenergy conversion device 100 as shown in FIG. 10, at the output ofrectifier 228 as shown in FIG. 9. The vertical axis of the graphrepresents the voltage differential between the outputs of the rectifier228. A reference line represents a zero voltage, with positive voltagesrepresented above the reference line and negative voltages below thereference line. The horizontal axis represents time. By theconfiguration of single-directional paths, as embodied in the diodes ofthe rectifier 228, the polarity of the voltage differences are alignedsuch that all voltage differences are output as positive voltages.

With reference to FIG. 12, a single wave-energy conversion device 100use is shown. In this embodiment, a single wave-energy conversion device100 is anchored to the sea-bed. Waves in the wave medium 104 cause thewave-energy conversion device 100 to output voltage. Typically, thisoutput voltage is transferred to electrical storage 222. The energy istransmitted by wire 234 to an output device 236, such as a light,transmitter or other electrical device.

In the embodiment shown, the output device 236 is a light on a buoy. Thelow power requirements of a simple device like a lamp make it feasibleto power the device with one or a few wave-energy conversion devices.The output device 236 may be a transmitter for use in a location system.As shown, without compensation for tidal effects, the wave-energyconversion device 100 may only provide power during high tide, or mayprovide significantly different levels of power at different times ofthe day, depending on the tide. Deeper water reduces the wave forcesimpacting the wave-energy conversion device.

With reference to FIG. 13, a wave-energy conversion system 200 use isshown. The wave-energy conversion system 200 is anchored to the oceanfloor 201. Waves in the wave medium 104 generate electrical power in thewave energy conversion devices 100 of wave energy conversion system 200.

The electrical energy generated by the wave energy conversion system 200is provided to output 240 which may rectify, regulate, store andotherwise control the energy for output. The output 240 is electricallyconnected to transmission wire 234. In the present embodiment, theoutput electrical energy is provided to electrical equipment 238. Theelectrical equipment 238 may be a transmitter, sensing devices,receiver, exploration and operation equipment.

Because the wave-energy conversion system 200 as shown includes tidalcompensation, the wave-energy conversion system 200 would provide fairlyconsistent energy outputs through the entire tidal cycle. This may beparticularly advantageous where the electrical equipment 238 requires asteady supply of energy.

With reference to FIG. 14, a wave-energy conversion system 200 use inaccordance with another embodiment is shown. The wave-energy conversionsystem 200 is anchored to the ocean floor 201. Waves in the wave medium104 generate electrical energy in the wave-energy conversion devices 100of the wave energy conversion system 200.

The electrical energy is output from the wave-energy conversion systemvia transmission wires 234 to shore output devices 242. The transmissionwire 234 may be an underground cable, a cable through the wave-medium orother forms of energy transmission suitable for transmitting energy fromthe wave-medium to the shore. The shore output devices 242 may beconnected to more than one wave-energy conversion system 200, to collectgreater amounts of energy for use.

With reference to FIG. 15, a cutaway side view of a magnetic sleeve 112in accordance with one embodiment is shown. Magnetic sleeve 112 includesa magnetized core section 244 and a insulation layer 248. The magneticsleeve 112 is fashioned as a hollow cylinder, with a cylindrical passage246 passing through the magnetic sleeve 112. The cylindrical passage 246is sized appropriately to allow free passage of the central wavedisplacement axle 102 through the magnetic sleeve 112. Attachment hooks256 are arranged on the upper end of the magnetic sleeve 112, forattachment of the magnetic sleeve 112 to the attachment lines 110.

Magnetized core section 244 may be made from a variety of magneticmaterials. The choice of magnetic materials may depend on the qualitiesof the magnetic materials in consideration with the details of thespecific embodiment implemented. Possible magnetic materials may includeFerrite magnets, NdFeB magnets, flexible magnets, injection bondedmagnets, SmCo magnets, Alnico magnets or other types of magneticmaterial. In accordance with the preferred embodiment, insulated ferritemagnets are advantageous in this regard.

Insulation layer 248 is typically used to prevent corrosion of themagnetic core section 224 by the wave medium 104. Insulation layer 248may also be used to provide electrical insulation, as necessary.Typically, a flexible plastic layer will be used as insulation, althoughthe materials chosen may reflect the nature of the wave medium, thematerial of the magnetic core section 224 and the nature of theinsulation required.

With reference to FIG. 16, a cutaway top view of a magnetic sleeve 112is shown. This view shows the circular portion of the cylindrical shapeof magnetic sleeve 112. The magnetic core section 244 is encased ininsulating layer 248. All of the outer surfaces of the magnetic sleeve112 are insulated, in accordance with one embodiment. The diameter ofthe cylindrical passage is preferably larger than the diameter of thecentral wave displacement axle 102. The insulation layer 248 providesphysical and electrical insulation.

With reference to FIG. 17, a cutaway top view of a magnetic sleeve 112with a bearing device 252 is shown. Because the generation of electricalenergy by the wave-energy conversion device depends on the motion of themagnetic sleeve 112 over the surface of the central wave displacementaxle 102. Depending on the environment where the wave-energy conversiondevice is deployed, the friction between the magnetic sleeve 112 and thecentral wave displacement axle 102 may exceed the specificationsrequired to generate energy.

Any of a variety of friction reducing substances or mechanisms may beused to reduce the friction between the magnetic sleeve 112 and thecentral wave displacement axle 102. In the shown embodiment, a bearingdevice 252 is shown as attached to the exterior of the magnetic sleeve112 within the cylindrical passage 246. Bearings 254 rotate with therelative motion of the magnetic sleeve 112 and the central wavedisplacement axle 102, thereby reducing the friction between them.

With reference to FIG. 18, a wave energy conversion device 100 inaccordance with another embodiment is shown. In this embodiment, themagnetic sleeve 112 is placed within the buoyant collar float 106, suchthat the movement of the buoyant collar float 106 relative to thecentral wave displacement axle 102 is translated into motion of themagnetic sleeve 112.

In accordance with one embodiment, the connection of central wavedisplacement axle 102 to the horizontal stabilization platform base 206may include a flexible connection 121. Flexible connection 121 maytypically include rubber or a similar flexible material. In accordancewith the preferred embodiment, the flexible connection 121 permits thecentral wave displacement axle 102 a small range of motion relative tothe horizontal stabilization platform base 206.

With reference to FIG. 19, a cross-section of a wave energy conversiondevice 100 in accordance with the embodiment shown in FIG. 18. The crosssection runs perpendicular to the axis of the central wave displacementaxle 102. The buoyant collar float 106 is cylindrically shaped. Themagnetic collar 112 is placed within the central opening of the buoyantcollar float 106.

With reference to FIG. 20, a wave energy conversion system 200 inaccordance with another embodiment is shown. In this embodiment, thehorizontal stabilization platform base 206 is attached to one or moretidal floats 210. The tidal floats 210 suspend the horizontalstabilization platform base 206 at a specified depth, relative to thetide level of the wave-medium 104. The horizontal stabilization platformbase 206 is typically anchored to the ocean floor 201 using an anchor202 and a chain 207. The anchor prevents the wave energy conversionsystem 200 from drifting beyond the reach of the chain 207.

It will be appreciated by those skilled in the art having the benefit ofthis disclosure that this invention provides a wave energy conversionsystem. It should be understood that the drawings and detaileddescription herein are to be regarded in an illustrative rather than arestrictive manner, and are not intended to limit the invention to theparticular forms and examples disclosed. On the contrary, the inventionincludes any further modifications, changes, rearrangements,substitutions, alternatives, design choices, and embodiments apparent tothose of ordinary skill in the art, without departing from the spiritand scope of this invention, as defined by the following claims. Thus,it is intended that the following claims be interpreted to embrace allsuch further modifications, changes, rearrangements, substitutions,alternatives, design choices, and embodiments.

1. A wave energy conversion system for converting wave energy within awave medium into electrical energy, comprising: a base connected to awave-medium floor; a tidal platform moveably connected to said base; atidal float connected to said tidal platform to stabilize said tidalplatform relative to said base and the surface of said wave medium suchthat said tidal platform can be maintained at a stabilized depth belowthe wave medium surface, an axle connected to said tidal platform andextending upward proximate to the surface of the wave medium; aninductive coil positioned proximate to the axle, such that an axis ofthe inductive coil is substantially parallel to the axle; a magneticsleeve including a magnetic sleeve opening and disposed slidingly aboutthe axel, such that the axle passes through the magnetic sleeve opening;and a float member interfaced with said magnetic sleeve; such that awave moving through the wave medium causes vertical displacement of thefloat member, causing the magnetic sleeve to move relative to theinductive coil and generate electrical energy within the inductive coil,and wherein said tidal float coupled with said tidal platform providesfor less movement of said tidal platform relative to said float member.2. The wave energy conversion system of claim 1, wherein said wavemedium is sea water.
 3. The wave energy conversion system of claim 1,further comprising an anchor for connecting said base to saidwave-medium floor.
 4. The wave energy conversion system of claim 3,wherein said anchor is made substantially of concrete.
 5. The waveenergy conversion system of claim 1, and further comprising a rodconnected to said base such that said rod is vertical relative to thewave-medium floor and extends up through a longitudinal sleeve fixed tosaid tidal platform such that movement of said tidal platform causessaid rod to reciprocate through said sleeve, said movement of said tidalplatform caused by said tidal float.
 6. The wave energy conversionsystem of claim 1, wherein said axle is formed as a hollow rod.
 7. Thewave energy conversion system of claim 6, wherein said inductive coil ispositioned within the hollow rod.
 8. The wave energy conversion systemof claim 1, wherein said magnetic sleeve is formed as a cylinder.
 9. Thewave energy conversion system of claim 1, wherein said float membercontains trapped gas.
 10. The wave energy conversion system of claim 1,further comprising a rectifier connected to the inductive coil.
 11. Awave energy conversion device for converting wave energy within a wavemedium having a wave medium surface into electrical energy, comprising:at least one tidal float supporting a stabilization platform in asubstantially horizontal position generally below the wave mediumsurface and relative thereto and operable to move said at least onetidal float and said platform as the wave medium surface increases ordecreases in distance relative to a wave medium bottom; a plurality ofaxles each containing at least one inductive coil, the plurality ofaxles connected to the stabilization platform in a substantiallyvertical position; a plurality of magnetic sleeves each coaxially andslidably attached to one of the plurality of axles, such that they movein a reciprocal manner relative to said associated at least oneinductive coil; and a plurality of magnetic sleeve floats, each oneinterfaced with one of the plurality of magnetic sleeves, and operableto allow said interfaced magnetic sleeves to move relative to theassociated one of said associated one of said axels as the result ofwave action on the wave medium surface and induce an electrical currentin said associated ones of said inductive coils.
 12. The device of claim11, further comprising at least one shaft interposing the platform andthe at least one tidal float for positioning the platform generallybelow the wave medium surface.
 13. The wave energy conversion device ofclaim 11, further comprising at least one base slidably engaged with thestabilization platform and adapted to prevent lateral movement of thestabilization platform.
 14. The wave energy conversion device of claim13, further comprising at least one anchor attached to the at least onebase for connecting the at least one base to the wave-medium floor. 15.The wave energy conversion device of claim 14, wherein the at least oneanchor is made substantially of concrete.
 16. The wave energy conversiondevice of claim 11, wherein each of the plurality of axles is formed asa hollow rod.
 17. The wave energy conversion device of claim 16, whereinthe at least one inductive coil of each of the plurality of axles ispositioned within the hollow rod.
 18. The wave energy conversion deviceof claim 11, wherein each of the plurality of magnetic sleeves is formedas a cylinder.
 19. The wave energy conversion device of claim 11,wherein each of the plurality of magnetic sleeve floats contains atrapped gas.
 20. The wave energy conversion device of claim 11, furthercomprising a rectifier conductively connected the at least one inductivecoil of each of the plurality of axles.